Flattened heat pipe

ABSTRACT

The flattened heat pipe includes a flattened tube, a first wick structure, a second wick structure and a working fluid. The flattened tube has an annular wall and a chamber formed within the annular wall. The first wick structure is disposed on a portion of the annular wall. The second wick structure is disposed on another portion of the annular wall, and not overlapping with each other. The working fluid is filled in the chamber.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates to heat pipes, particularly to flattened heat pipes used for transferring heat from a heat source.

2. Related Art

Heat pipes, which are used for heat sources such as CPUs, can effectively overcome more and more heat generated from electronic heat sources. Thus heat pipes have become necessary for heat sinks with high efficiency of heat dissipation. In recent years, portable electronic devices are very popular around the world. As a result, heat sinks must be continuously improved to satisfy their requirements.

A typical heat pipe includes a circular tube, a wick structure and a working fluid. A chamber is formed in the circular tube. The wick structure is attached on an inner side of the tube. The working fluid is filled in the chamber and contained in the wick structure.

However, the circular tube is not suitable for thinned electronic devices. Further, the wick structure is of a single type, so it will make the internal heated vapor flows too fast when its density is large. This will cause dryout easily. When the density of the wick structure is small, the heated vapor flows too slowly. This will decrease the efficiency of heat transfer.

SUMMARY OF THE INVENTION

An object of the invention is to provide a flattened heat pipe, which can increase flowing speed of the internal vapor and liquid and improve efficiency of heat transfer.

To accomplish the above object, the flattened heat pipe of the invention includes a flattened tube, a first wick structure, a second wick structure and a working fluid. The flattened tube has an annular wall and a chamber formed within the annular wall. The first wick structure is disposed on a portion of the annular wall. The second wick structure is disposed on another portion of the annular wall, and not overlapping with each other. The working fluid is filled in the chamber.

To accomplish the above object, the flattened heat pipe of the invention includes a flattened tube, a first wick structure, a second wick structure and a working fluid. The flattened tube has an annular wall and a chamber formed within the annular wall. The first wick structure is disposed on a portion of the annular wall and continuously over a front half and a rear half of the flattened tube. The second wick structure is disposed on another portion of the annular wall and continuously over a front half and a rear half of the flattened tube, and not overlapping with each other and not overlapping with each other. The working fluid is filled in the chamber.

The invention arranges two layers of wick structures with different density. This can promote the vapor to flow fast and add volume of the internal liquid contained in the wick structure for preventing from dryouting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the invention;

FIG. 2 is a sectional view of the first embodiment of the invention;

FIG. 3 is a sectional view of the second embodiment of the invention;

FIG. 4 is a sectional view of the third embodiment of the invention;

FIG. 5 is a sectional view of the fourth embodiment of the invention;

FIG. 6 is a sectional view of the fifth embodiment of the invention;

FIG. 7 is a sectional view of the sixth embodiment of the invention; and

FIG. 8 is a sectional view of the seventh embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Please refer to FIGS. 1 and 2. The flatten heat pipe of the invention includes a flattened tube 10, a first wick structure 20, a second wick structure 30 and a working fluid 40.

The flattened tube 10 is made of copper, aluminum or their alloys with great thermo-conductivity and tractility. The tube 10 of the shown embodiment is of a strip shape and composed of an upper sheet 11, a lower sheet 12 and two arcked sheets 13 connecting therebetween. These sheets 11, 12, 13 constitute an annular wall 10 a. Two ends of the tube 10 are sealed by welding. A chamber 14 is formed within the sheets 11, 12, 13. The overall height of the upper sheet 11, the lower sheet 12 and the chamber 14 is less than 2 mm.

The first wick structure 20 is a plurality of grooves 201 formed on the right area of the upper sheet 11 and the lower sheet 12 and the right arcked sheet 13. The first wick structure 20 continuously covers the front half and the rear half of the tube 10 along an axis of the tube 10. The second wick structure 30 is attached on the left area of the upper sheet 11 and the lower sheet 12 and the left arcked sheet 13. Also, the second wick structure 30 continuously covers the front half and the rear half of the tube 10 along an axis of the tube 10. The second wick structure 30 is sintered metal powder and does not overlap with the first wick structure 20. However, edges of the first and second wick structures 20, 30 may be in contact with each other as shown in the figures or may be out of contact with each other.

The working fluid 40 may be pure water or alcohol filled in the chamber 14. At a room temperature, the working fluid 40 is liquid and contained in the wick structures 20, 30. The working fluid 40 will be evaporated to transfer a large amount of heat to an area with lower temperature when it is heated.

Please refer to FIG. 3, which shows the second embodiment of the invention. In this embodiment, the first wick structure 20 is a plurality of grooves 201 formed on the right area of the upper sheet 11 and the lower sheet 12 and the right arcked sheet 13. The second wick structure 30 a is attached on the left area of the upper sheet 11 and the lower sheet 12 and the left arcked sheet 13. The second wick structure 30 a is a mesh structure woven by metal wires. The mesh structure does not overlap with the grooves 201 as the first wick structure 20.

Please refer to FIG. 4, which shows the third embodiment of the invention. In this embodiment, the first wick structure 20 is a plurality of grooves 201 formed on the right area of the upper sheet 11 and the lower sheet 12 and the right arcked sheet 13. The second wick structure 30 b is a bundle of fibers attached on the left area of the upper sheet 11 and the lower sheet 12 and the left arcked sheet 13. The bundle of fibers does not overlap with the grooves 201 as the first wick structure 20.

Please refer to FIG. 5, which shows the fourth embodiment of the invention. In this embodiment, the first wick structure 20 a is attached on the right area of the upper sheet 11 and the lower sheet 12 and the right arcked sheet 13. The first wick structure 20 a is formed by sintered metal powder with a plurality of grooves 201 a. The second wick structure 30 is the same as the first embodiment.

Please refer to FIG. 6, which shows the fifth embodiment of the invention. In this embodiment, the first wick structure 20 b is attached on the right area of the upper sheet 11 and the lower sheet 12, the right arcked sheet 13 and the right portion of the chamber 14. The first wick structure 20 b is formed by sintered metal powder. The second wick structure 30 a is the same as the second embodiment, thereby volume of the liquid contained in the wick structures 20 b, 30 a can be increased.

Please refer to FIG. 7, which shows the sixth embodiment of the invention. In this embodiment, the first wick structure 20 c is attached on the right area of the upper sheet 11 and the lower sheet 12 and the right arcked sheet 13. The first wick structure 20 c is a mesh structure. The second wick structure 30 c is attached on the left area of the upper sheet 11 and the lower sheet 12 and the left arcked sheet 13. The second wick structure 30 c is a mesh structure, too. A pair of third wick structures 50 are separately disposed on the middle portions of the upper and lower sheets 11, 12. The pair of third wick structures 50 are made of sintered metal powder and in contact with each other. Other arrangements and shapes are available. The two third wick structures 50 may be out of contact with each other (not shown). The third wick structures 50 can increase volume of the liquid contained therein to prevent from dryouting.

Please refer to FIG. 8, which shows the seventh embodiment of the invention. In this embodiment, the first wick structure 20 is a plurality of grooves 201 formed on the right area of the upper sheet 11 and the lower sheet 12 and the right arcked sheet 13. The second wick structure 30 d is attached on the left area of the upper sheet 11 and the lower sheet 12 and the left arcked sheet 13. The second wick structure 30 d is sintered metal powder. Additionally, the middle portion of the upper sheet 11 is formed with a smooth surface 60 for increasing vapor flow space and reducing vapor flow resistance.

It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims. 

What is claimed is:
 1. A flattened heat pipe comprising: a flattened tube, having an annular wall and a chamber formed within the annular wall; a first wick structure, disposed on a portion of the annular wall; a second wick structure, disposed on another portion of the annular wall, and not overlapping with each other; and a working fluid filled in the chamber.
 2. The flattened heat pipe of claim 1, wherein the flattened tube has two parallel sheets, and an overall height of the two sheets and the chamber is less than 2 mm.
 3. The flattened heat pipe of claim 1, wherein the first wick structure is a plurality of grooves formed on the annular wall, and the second wick structure is sintered metal powder attached on the annular wall.
 4. The flattened heat pipe of claim 1, wherein the first wick structure is a plurality of grooves formed on the annular wall, and the second wick structure is a mesh structure attached on the annular wall.
 5. The flattened heat pipe of claim 1, wherein the first wick structure is a plurality of grooves formed on the annular wall, and the second wick structure is a bundle of fibers attached on the annular wall.
 6. The flattened heat pipe of claim 1, wherein the first wick structure is sintered metal powder attached on the annular wall, and the second wick structure is sintered metal powder attached on the annular wall and formed with a plurality of grooves.
 7. The flattened heat pipe of claim 1, wherein the first wick structure is a mesh structure attached on the annular wall, and the second wick structure is sintered metal powder attached on the annular wall.
 8. The flattened heat pipe of claim 1, further comprising a pair of third wick structures, wherein the first wick structure is a mesh structure attached on the annular wall, the second wick structure is a mesh structure attached on the annular wall, and the third wick structures are separately attached on a remaining area of the annular wall, are out of contact with each other and do not overlap with the first and second wick structures.
 9. The flattened heat pipe of claim 1, further comprising a pair of third wick structures, wherein the first wick structure is a mesh structure attached on the annular wall, the second wick structure is a mesh structure attached on the annular wall, and the third wick structures are separately attached on a remaining area of the annular wall, are in contact with each other and do not overlap with the first and second wick structures.
 10. The flattened heat pipe of claim 1, wherein the first wick structure is a plurality of grooves formed on the annular wall, the second wick structure is sintered metal powder attached on the annular wall, and a remaining portion of the annular wall is formed with a smooth surface.
 11. A flattened heat pipe comprising: a flattened tube, having an annular wall and a chamber formed within the annular wall; a first wick structure, disposed on a portion of the annular wall and continuously over a front half and a rear half of the flattened tube; a second wick structure, disposed on another portion of the annular wall and continuously over a front half and a rear half of the flattened tube, and not overlapping with each other; and a working fluid filled in the chamber.
 12. The flattened heat pipe of claim 11, wherein the flattened tube has two parallel sheets, and an overall height of the two sheets and the chamber is less than 2 mm.
 13. The flattened heat pipe of claim 11, wherein the first wick structure is a plurality of grooves formed on the annular wall, and the second wick structure is sintered metal powder attached on the annular wall.
 14. The flattened heat pipe of claim 11, wherein the first wick structure is a plurality of grooves formed on the annular wall, and the second wick structure is a mesh structure attached on the annular wall.
 15. The flattened heat pipe of claim 11, wherein the first wick structure is a plurality of grooves formed on the annular wall, and the second wick structure is a bundle of fibers attached on the annular wall.
 16. The flattened heat pipe of claim 11, wherein the first wick structure is sintered metal powder attached on the annular wall, and the second wick structure is sintered metal powder attached on the annular wall and formed with a plurality of grooves.
 17. The flattened heat pipe of claim 11, wherein the first wick structure is a mesh structure attached on the annular wall, and the second wick structure is sintered metal powder attached on the annular wall.
 18. The flattened heat pipe of claim 11, further comprising a pair of third wick structures, wherein the first wick structure is a mesh structure attached on the annular wall, the second wick structure is a mesh structure attached on the annular wall, and the third wick structures are separately attached on a remaining area of the annular wall, are out of contact with each other and do not overlap with the first and second wick structures.
 19. The flattened heat pipe of claim 11, further comprising a pair of third wick structures, wherein the first wick structure is a mesh structure attached on the annular wall, the second wick structure is a mesh structure attached on the annular wall, and the third wick structures are separately attached on a remaining area of the annular wall, are in contact with each other and do not overlap with the first and second wick structures.
 20. The flattened heat pipe of claim 11, wherein the first wick structure is a plurality of grooves formed on the annular wall, the second wick structure is sintered metal powder attached on the annular wall, and a remaining portion of the annular wall is formed with a smooth surface. 